Method for manufacturing perovskite nanocrystal particle light emitting body where organic ligand is substituted, nanocrystal particle light emitting body manufactured thereby, and light emitting device using same

ABSTRACT

Provided are a method for manufacturing a perovskite particle light-emitter where an organic ligand is substituted, a light-emitter manufactured thereby, and a light emitting device using the same. A method for manufacturing an hybrid perovskite particle light-emitter where an organic ligand is substituted may comprise the steps of: preparing a solution including an hybrid perovskite particle light-emitter, wherein the hybrid perovskite particle light-emitter comprises an halide perovskite nanocrystal structure and a plurality of first organic ligands surrounding the perovskite nanocrystal structure; and adding, to the solution, a second organic ligand which is shorter than the first organic ligands or includes a phenyl group or a fluorine group, thereby substitutes the first organic ligands with the second organic ligand. Thus, since energy transfer or charge injection into the nanocrystal structure increases through ligand substitution, it is possible to further increase light emitting efficiency and increase durability and stability by means of a hydrophobic ligand.

TECHNICAL FIELD

The present invention relates to a light-emitter and a light emittingdevice using the same, and more particularly, to a method formanufacturing an hybrid perovskite or an inorganic metal halideperovskite particle light-emitter where an organic ligand issubstituted, a particle light-emitter manufactured thereby, and a lightemitting device using the same.

BACKGROUND ART

The major trend of the display market is shifting from the existinghigh-efficiency and high-resolution-oriented display, to the emotionalimage-quality display aiming at realizing a high color purity fordemonstration of natural colors. In this respect, organiclight-emitter-based organic light emitting diode (OLED) devices haveremarkably developed, inorganic quantum dot LEDs with the improved colorpurity have been actively researched and developed as alternatives.However, in the viewpoint of emitting materials, both the organiclight-emitters and the inorganic quantum dot light-emitters haveintrinsic limitations.

The existing organic light-emitters have an advantage of highefficiency, but the existing organic light-emitters have a wide spectrumand poor color purity. Although the inorganic quantum dot light-emittershave been known to have good color purity because the luminescenceoccurs by quantum size effects, there is a problem that it is difficultto uniformly control the sizes of the quantum dots as the colorapproaches the blue color, and thereby the size distributiondeteriorates the color purity. Furthermore, because the inorganicquantum dots have a very deep valence band, there is a problem that itis difficult to inject holes because a hole injection barrier from anorganic hole injection layer or an anode is too large. Also, the twolight-emitter are disadvantageously expensive. Thus, there is a need fornew types of hybrid light-emitters that compensate for the disadvantagesof the organic light-emitters and inorganic quantum dot emitters andmaintains their merits.

Since the hybrid light materials have advantages of low manufacturingcosts and simple manufacturing and device manufacturing processes andalso have all advantages of organic emitting materials, which are easyto control optical and electrical properties, and inorganic emittingmaterials having high charge mobility and mechanical and thermalstability, the hybrid emitting materials are attracting attentionacademically and industrially.

Among them, since the hybrid perovskite materials (hereafter, hybridperovskite) have high color purity (full width at half maximum (FWHM)≈20nm), simple color control, and low synthesis costs, the hybridperovskite materials are very likely to be developed as thelight-emitter. Since the high color purity from these materials can berealized because they have a layered structure in which atwo-dimensional (2D) plane made of the inorganic material is sandwichedbetween 2D planes made of the organic material, and a large differencein dielectric constant between the inorganic material and the organicmaterial is large (ε_(organic)≈2.4, ε_(inorganic)≈6.1) so that theelectron-hole pairs (or excitons) are bound to the inorganic 2D layer.

A material having the conventional perovskite structure (ABX₃) isinorganic metal oxide.

In general, the inorganic metal oxides are oxides, for example,materials in which metal (alkali metals, alkali earth metals,lanthanides, etc) cations such as Ti, Sr, Ca, Cs, Ba, Y, Gd, La, Fe, andMn, which have sizes different from each other, are located in A and Bsites, oxygen anions are located in an X site, and the metal cations inthe B site are bonded to the oxygen anions in the X site in thecorner-sharing octahedron form with the 6-fold coordination. Examples ofthe inorganic metal oxides include SrFeO₃, LaMnO₃, CaFeO₃, and the like.

On the other hand, since the hybrid perovskite has the ABX₃ in whichorganic ammonium (RNH₃) cations (or “A site cation” in perovskitecrystals) are located in the A site, and halides (Cl, Br, I) are locatedin the X site to form the organic metal halide perovskite material, thehybrid perovskite are completely different from the inorganic metaloxide perovskite material in composition.

In addition, the materials vary in characteristics due to a differencein composition of the materials. The inorganic metal oxide perovskitetypically has characteristics of superconductivity, ferroelectricity,colossal magnetoresistance, and the like, and thus has been generallyconducted to be applied for sensors, fuel cells, memory devices, and thelike. For example, yttrium barium copper oxides have superconducting orinsulating properties according to oxygen contents.

On the other hand, since the hybrid perovskite (or inorganic metalhalide perovskite) has a structure in which the organic planes ((or “Asite cation” plane in the perovskite crystal structure)) and theinorganic planes are alternately stacked and thus has a structuresimilar to a lamellar structure so that the excitons are bound in theinorganic plane, it may be an ideal light-emitter that generally emitslight having very high purity by the crystal structure itself ratherthan the quantum size effect of the material.

If the hybrid perovskite has a chromophore (mainly including aconjugated structure) in which organic ammonium has a bandgap less thanthat of a crystal structure composed of a central metal and a halogencrystal structure (BX₆), the luminescence occurs in the organicammonium. Thus, since light having high color purity is not emitted, afull width at half maximum of the luminescence spectrum becomes widerthan 50 nm. Therefore, the hybrid perovskite are unsuitable for a lightemitting layer. Thus, in this case, it is not very suitable for thelight-emitter having the high color purity, which is highlighted in thispatent. Therefore, in order to produce the light-emitter having thehighcolor purity, it is important that the luminescence occurs in aninorganic lattice composed of the central metal-halogen elements withoutthe organic ammonium which contain the chromophore. That is, this patentfocuses on the development of the light-emitter having high color purityand high efficiency in the inorganic lattice. For example, although anelectroluminescent device in which a dye-containing hybrid material isformed in the form of a thin film rather than that of a particle andused as a light emitting layer, the emission originated from theemitting dye itself, not the intrinsic crystal structure as disclosed inKorean Patent Publication No. 10-2001-0015084 (Feb. 26, 2001), light isnot emitted from the perovskite lattice structure.

However, since the hybrid perovskite has small exciton binding energy,there is a fundamental problem that the luminescence occurs at a lowtemperature, but the excitons do not efficiently emit light at roomtemperature due to thermal ionization and delocalization of chargecarriers and thus are separated into free charge carriers and thenannihilated. Also, there is a problem in that the excitons areannihilated by the layer having high conductivity in the vicinity of theexcitons when the free charges are recombined again to form excitons.Therefore, to improve light emission efficiency and brightness of thehybrid or metal halide perovskite-based LED, it is necessary to preventthe excitons from being quenched.

DISCLOSURE OF THE INVENTION Technical Problem

To solve the abovementioned problems, the present invention provides aparticle light-emitter having improved luminescent efficiency anddurability (or stability) by synthesizing hybrid perovskite or inorganicmetal halide perovskite into nanocrystal made of at least ternarycompounds in unit crystal (≥3 components) (i.e. perovskite structure)instead of forming a polycrystal thin film in order to prevent thermalionization, delocalization of charge carriers, and quenching ofexcitons, and a light emitting device using the same.

Furthermore, the present invention provides a particle light-emitter inwhich an organic ligand surrounding a hybrid perovskite or inorganicmetal halide perovskite nanocrystal structure is substituted with aligand having a short length or a ligand including a phenyl group or afluorine group to more improve light emitting efficiency and a lightemitting device using the same.

Technical Solution

To achieve the objectives, one aspect of the present invention providesa method for manufacturing a hybrid perovskite particle light-emitter,in which an organic ligand is substituted. The method for manufacturingthe hybrid perovskite particle light-emitter, in which the organicligand is substituted, includes steps of: preparing a solution includingthe hybrid perovskite particle light-emitters that have an halideperovskite nanocrystal structure and a plurality of first organicligands surrounding a surface of the hybrid or metal halide perovskitenanocrystal structure substitutionally or separately; and adding asecond organic ligand, which has a length less than that of each of thefirst organic ligands or includes a phenyl group or fluorine group, tothe solution to substitute the first organic ligand with the secondorganic ligand.

Also, each of the first organic ligand and the second organic ligand mayinclude alkyl halide, and a halogen element of the second organic ligandmay include an element having affinity higher than that of a halogenelement of the first organic ligand with respect to a center metal (Bsite) or A site of the halide perovskite nanocrystal structure.

Also, the hybrid perovskite particle may have a size of 1 nm to 900 nm.

Also, the hybrid perovskite particle may have bandgap energy determinedby the crystal structure without depending on a particle size.

Also, the preparing of the solution including the hybrid perovskiteparticle light-emitter may include steps of: preparing a first solutionin which hybrid perovskite is dissolved in a polar solvent and a secondsolution in which an alkyl halide surfactant is dissolved in a non-polarsolvent; and mixing the first solution with the second solution to formthe hybrid perovskite particle light-emitter.

Also, the hybrid perovskite may include a structure of ABX₃, A₂BX₄,AnBX_(2+n), ABX₄, A₂BB′X₆, or A_(n−1)Pb_(n)X_(3n+1) (where n is aninteger between 2 to 6, and the A may be an organic ammonium orinorganic alkali metal material, the B may be a metal material, and theX may be a halogen element. Also, the A may be (CH₃NH₃)_(n),((C_(x)H_(2x+1))_(n)NH₂)(CH₂NH₃)_(n), (NH₂)₂, (C_(n)H_(2n+1)NH₃)₂,CF₃NH₃, (CF₃NH₃)_(n),((C_(x)F_(2x+1))_(n)NH₂)₂(CF₂NH₃)_(n)((C_(x)F_(2x+1))_(n)NH₃),(C_(n)F_(2n+1)NH₃), (CH(NH₂)₂), C_(x)H_(2x+1)(C(NH₂)₂) Cs, Rb, K, orderivative thereof (R is alkyl or fluoroalkyl, where n is an integerequal to or greater than 1, and x is an integer equal to or greater than1), the B or B′ may be a divalent transition metal, a rare earth metal,an alkali earth metal, Pb, Sn, Ge, Ga, In, Al, Sb, Bi, Po, or acombination thereof, and the X may be Cl, Br, I, or a combinationthereof.

To achieve the objectives, another aspect of the present inventionprovides a hybrid perovskite particle light-emitter, in which an organicligand is substituted. The hybrid perovskite particle light-emitter, inwhich the organic ligand is substituted, may be manufactured by theabovementioned method.

The hybrid perovskite particle light-emitter, in which an organic ligandis substituted, may be dispersible in an organic solvent.

The organic solvent may include a polar solvent and a non-polar solvent,the polar solvent may include dimethylformamide, gamma butyrolactone,N-methylpyrrolidone, dimethylsulfoxide or isopropyl alcohol, and thenon-polar solvent may include dichloroethylene, trichlorethylene,chloroform, chlorobenzene, dichlorobenzene, styrene, xylene, toluene, orcyclohexene.

To achieve the objectives, another aspect of the present inventionprovides a light emitting device. The light emitting device includes: afirst electrode; a second electrode; and a light emitting layer disposedbetween the first electrode and the second electrode and including theabovementioned hybrid perovskite particle light-emitter, in which theorganic ligand is substituted.

To achieve the objects, another aspect of the present invention providesa method for manufacturing an inorganic metal halide perovskite particlelight-emitter, in which an organic ligand is substituted. The method formanufacturing an inorganic metal halide perovskite particlelight-emitter, in which the organic ligand is substituted, includessteps of: preparing a solution including the inorganic metal halideperovskite particle light-emitters that have an inorganic metal halideperovskite nanocrystal structure and a plurality of first organicligands surrounding a surface of the inorganic metal halide perovskitenanocrystal structure; and adding a second organic ligand, which has alength less than that of each of the first organic ligands or includes aphenyl group or fluorine group, to the solution to substitute the firstorganic ligand with the second organic ligand.

To achieve the objectives, another aspect of the present inventionprovides a solar cell. The solar cell includes: a first electrode; asecond electrode; and a photoactive layer disposed between the firstelectrode and the second electrode and including the abovementionedhybrid perovskite particle light-emitter, ligand is substituted.

Each of the first organic ligand and the second organic ligand mayinclude alkyl halide, and a halogen element of the second organic ligandmay include an element having affinity equal to or higher than that of ahalogen element of the first organic ligand with respect to a centermetal (B site) or A site of the halide perovskite nanocrystal structure.The inorganic metal halide perovskite may include a structure of ABX₃,A₂BX₄, ABX₄, A_(n)BX_(2+n) A₂BB′X₆, or A_(n−1)Pb_(n)X_(3n+1) (where n isan integer between 2 to 6), and the A may be an alkali metal, the B maybe a metal material, and the X may be a halogen element.

Here, the A may be Na, K, Rb, Cs, or Fr, the B may be B may be adivalent transition metal, a rare earth metal, an alkali earth metal,Pb, Sn, Ge, Ga, In, Al, Sb, Bi, Po, or a combination thereof, and the Xmay be Cl, Br, I, or a combination thereof.

Advantageous Effects

In the particle light-emitters that have the hybrid perovskite (or theinorganic metal halide perovskite) nanocrystal structure, the hybridperovskite having the crystal structure, in which the FCC and the BCCare combined with each other, may be formed in the particlelight-emitter to form a lamellar structure in which the organic plane(or “A site cation” plane in the perovskite crystal structure) and theinorganic plane are alternately stacked, and also, the excitons may beconfined in the inorganic plane to implement the high color purity.

Also, the exciton diffusion length may be reduced, and the excitonbinding energy may increase in the nanocrystal structure having a sizeof 900 nm or less to prevent the excitons from being annihilated bythermal ionization and the delocalization of the charge carriers,thereby improving the luminescent efficiency at room temperature.

Furthermore, when compared to the hybrid perovskite having the 3Dstructure such as the ABX₃ structure, the halide perovskite nanocrystalhaving the 2D structure such as the A₂BX₄, ABX₄, A_(n-1)B_(n)X_(3n+1)structure may be synthesized to increase the distance between theinorganic planes confined in the excitons, resulting in increasing inthe exciton binding energy, thereby improving the luminescent efficiencyand the durability (or stability).

Also, the bandgap energy of the hybrid perovskite particle may bedetermined by the crystal structure without depending on the particlesize.

Also, the organic or inorganic ligand surrounding the hybrid perovskiteor inorganic metal halide perovskite nanocrystal structuresubstitutionally or separately may be substituted with the ligand havingthe short length or the ligand including the phenyl group or thefluorine group to more increase the energy transfer or the chargeinjection in the nanocrystal structure, thereby improving theluminescent efficiency and the durability (or stability) by thehydrophobic ligands.

The effects of the present invention are not limited to theaforementioned effects, but other objects not described herein will beclearly understood by those skilled in the art from descriptions below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a perovskite nanocrystal structureaccording to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a method for manufacturing the hybridperovskite particle light-emitter, in which an organic ligand issubstituted, according to an embodiment of the present invention.

FIG. 3 is a flowchart illustrating a method for manufacturing the hybridperovskite particle light-emitter according to an embodiment of thepresent invention.

FIG. 4 is a schematic view illustrating a method for method formanufacturing the hybrid perovskite particle light-emitter according toan embodiment of the present invention.

FIG. 5 is a schematic view of a hybrid perovskite particle light-emitterand an inorganic metal halide perovskite particle light-emitteraccording to an embodiment of the present invention.

FIG. 6 is a schematic view illustrating a method for manufacturing thehybrid perovskite particle light-emitter, in which the organic ligand issubstituted, according to an embodiment of the present invention.

FIG. 7 is a fluorescent image obtained by photographing emission lightby irradiating ultraviolet rays onto a light-emitter according toManufacturing Example 1, Comparative Example 1, and Comparative Example2.

FIG. 8 is a schematic view of a light-emitter according to ManufacturingExample 1 and Comparative Example 1.

FIG. 9 is an image obtained by photographing a photoluminescence matrixof the light-emitter at room temperature and a low temperature accordingto Manufacturing Example 30 and Comparative Example 1.

FIG. 10 is a graph obtained by photographing photoluminescence of thelight-emitter according to Manufacturing Example 1 and ComparativeExample 1.

FIG. 11 is a schematic view of the hybrid perovskite Particlelight-emitter, in which the organic ligand is substituted, according toan embodiment of the present invention.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described indetail with reference to the accompanying drawings.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

In the following description, it will be understood that when an elementsuch as a layer, a region, or substrate is referred to as being ‘on’another layer, region, or substrate, it can be directly on the otherlayer, region, or substrate, or intervening layers, regions, orsubstrates may also be present.

Although the terms such as “first,” “second,” etc., are used to describevarious element, components, regions, layers, and/or portions, it isobvious that the elements, components, regions, layers, and/or portionsshould not be defined by these terms.

FIG. 1 is a schematic view of a perovskite nanocrystal structureaccording to an embodiment of the present invention.

FIG. 1 illustrates structures of a halide perovskite nanocrystal and aninorganic metal halide perovskite nanocrystal.

Referring to FIG. 1 the halide perovskite nanocrystal has a structurewith a center metal centered in a face centered cubic (FCC), in whichsix inorganic halide materials X are respectively located on allsurfaces of a hexahedron, and in a body centered cubic (BCC), in whicheight organic ammonium OA are respectively located at all vertexes of ahexahedron. Here, Pb is illustrated as an example of the center metal.

Also, the inorganic metal halide perovskite nanocrystal has structurewith a center metal centered in a face centered cubic (FCC), in whichsix inorganic halide materials X are respectively located on allsurfaces of a hexahedron, and in a body centered cubic (BCC), in whicheight alkali metals are respectively located at all vertexes of ahexahedron. Here, Pb is illustrated as an example of the center metal.

Here, all sides of the hexahedron have an angle of 90° with respect toeach other. The above-described structure may include a cubic structurehaving the same length in horizontal, vertical, and height directionsand a tetragonal structure having different lengths in the horizontal,vertical, and height directions.

Thus, a two-dimensional (2D) structure according to According to thepresent invention may be the halide perovskite nanocrystal structurewith a center metal centered in a face centered cubic, in which sixinorganic halide materials X are respectively located on all surfaces ofa hexahedron, and in a body centered cubic, in which eight organicammonium are respectively located at all vertexes of a hexahedron and bedefined as a structure of which a horizontal length and a verticallength are the same, but a height length is longer by 1.5 times or morethan each of the horizontal length and the vertical length.

A method for manufacturing the hybrid perovskite particle light-emitter,in which the organic ligand is substituted, according to an embodimentof the present invention will be described.

FIG. 2 is a flowchart illustrating a method for manufacturing the hybridperovskite particle light-emitter, in which an organic ligand issubstituted, according to an embodiment of the present invention.

Referring to FIG. 2, the method for manufacturing the hybrid perovskiteparticle light-emitter, in which an organic ligand is substituted,includes a step (S100) of preparing a solution including a halideperovskite nanocrystal light-emitter and a step (S200) of substituting afirst organic ligand of the halide perovskite nanocrystal light-emitterwith a second organic ligand in the solution.

In more detail, first, a solution including an halide perovskitenanocrystal light-emitter is prepared (S100). The hybrid perovskitenanocrystal light-emitter may include a plurality of first organicligands surrounding a hybrid or metal halide perovskite nanocrystalstructure and the halide perovskite nanocrystal structure.

The step of preparing the solution including the hybrid perovskitenanocrystal light-emitter may be a step of manufacturing and preparingthe hybrid perovskite nanocrystal light-emitter. One manufacturingexample will be described with reference to FIGS. 3 to 5.

FIG. 3 is a flowchart illustrating a method for manufacturing the hybridperovskite particle light-emitter according to an embodiment of thepresent invention.

Referring to FIG. 3, the hybrid perovskite particle light-emitteraccording to the present invention may be manufactured through aninverse nano-emulsion method, reprecipitation method, or hot injectionmethod.

First, the first solution in which the hybrid perovskite is dissolved ina polar solvent and the second solution in which a surfactant isdissolved in a non-polar solvent are prepared (S110).

Here, the polar (aprotic or protic) solvent may includedimethylformamide, gamma butyrolactone, N-methylpyrrolidone,dimethylsulfoxide or isopropyl alcohol, but is not limited thereto.

Also, the hybrid perovskite may be a material having a 2D crystallinestructure, a 3D crystalline structure or a combination thereof.

For example, the hybrid perovskite having the 3D crystal structure maybe an ABX₃ structure. Also, the hybrid perovskite having the 2D crystalstructure may be a structure of ABX3, A2BX4, ABX4, AnBX2+nr A2BB′X6, orAn−1PbnX3n+1 (where n is an integer between 2 to 6).

Here, the A is an organic ammonium or inorganic alkali metal material,the B is a metal material, and the X is a halogen element.

For example, the A may be (CH3NH3)_(nr) (CxH2x+1)nNH2) (CH₂NH₃)_(n),R(NH₂)₂, (CnH2n+1NH3)2, CF3NH3, (CF3NH3)_(nr)(C_(x)F_(2x+1))_(n)NH₂)₂(CF₂NH₃) ((CxF2x+1)nNH3), (CnF2n+1NH3),(CH(NH2)2), CxH₂x+1 (C(NH₂)2), Cs, Rb, K, metal or derivative thereof (Ris alkyl or fluoroalkyl, where n is an integer equal to or greater than1, and x is an integer equal to or greater than 1). Here, the B may be adivalent transition metal, a rare earth metal, an alkali earth metal,Pb, Sn, Ge, Ga, In, Al, Sb, Bi, Po, or a combination thereof. Here, therare earth metal may be, for example, Ge, Sn, Pb, Eu, or Yb. Also, thealkali earth metal may be, for example, Ca or Sr. Also, the X may be Cl,Br, I, or a combination thereof.

The perovskite may be prepared by combining the AX with BX₂ at apredetermined ratio. That is, the first solution may be formed bydissolving the AX and BX₂ in the polar solvent at a predetermined ratio.For example, the AX and BX₂ may be dissolved in the polar solvent at aratio of 2:1 to prepare the first solution in which the A₂BX₄ hybridperovskite is dissolved.

Also, it is preferable that the hybrid perovskite uses a material havinga 2D crystal structure rather than a 2D crystal structure.

When the hybrid perovskite having the 2D structure is formed to have thenanocrystal in comparison that the hybrid perovskite having the 3Dstructure is formed to have the nanocrystal, the inorganic plane and theorganic plane, which are stacked on each other, may be clearlydistinguished from each other to more firmly confine the exciton in theinorganic plane with respect to the organic plane and thereby to improveluminescent efficiency and durability (or stability), therebyimplementing higher color purity.

Also, the non-polar solvent may include dichloroethylene,trichlorethylene, chloroform, chlorobenzene, dichlorobenzene, styrene,xylene, toluene, or cyclohexene, but is not limited thereto.

Also, the alkyl halide surfactant may have a structure of alkyl-X. Here,the halogen element corresponding to the X may include Cl, Br, or I.Also, the alkyl structure may include acyclic alkyl having a structureof CnH₂n+1, primary alcohol having a structure such as C_(n)H_(2n+1)OH,secondary alcohol, tertiary alcohol, alkylamine having a structure ofalkyl-N (e.g.′ hexadecyl amine, 9-Octadecenylamine 1-Amino-9-octadecene(C₁₉H₃₇N)), p-substituted aniline, phenyl ammonium, or fluorineammonium, but is not limited thereto.

A carboxylic acid (COOH) and amines (NH3) surfactant may be used insteadof the alkyl halide surfactant.

For example, the surfactant may include a carboxylic acid such as a4,4′-Azobis(4-cyanovaleric acid), an acetic acid, a 5-aminosalicylicacid, an acrylic acid, an L-aspentic acid, a 6-bromohexanoic acid, abromoacetic acid, a dichloro acetic acid, an ethylenediaminetetraaceticacid, an isobutyric acid, an itaconic acid, a maleic acid, anr-maleimidobutyric acid, an L-malic acid, a 4-Nitrobenzoic acid, anamino acid, a 1-pyrenecarboxylic acid, or an oleic acid, but is notlimited thereto.

Next, the first solution may be mixed with the second solution to formthe particle. (S200).

In the step of mixing the first solution with the with the secondsolution to form the particle, it is preferable to mix the firstsolution by dropping into the second solution in drops. Also, the secondsolution may be stirred. For example, the second solution in which thehybrid perovskite is dissolved may be slowly added dropwise into thesecond solution in which the alkyl halide surfactant that is beingstrongly stirred is dissolved to synthesize the particle.

In this case, when the first solution drops to be mixed with the secondsolution, the hybrid perovskite (shortly “perovskite”) is precipitatedfrom the second solution due to a difference in solubility. Also, asurface of the hybrid perovskite precipitated from the second solutionis surrounded by the alkyl halide surfactant and thus stabilized togenerate a halide perovskite nanocrystal (perovskite-NC) that is welldispersed. Thus, the hybrid perovskite particle light-emitter includingthe halide perovskite nanocrystal structure and the plurality of alkylhalide organic ligands or inorganic binary compounds or combinationthereof surrounding the halide perovskite nanocrystal structure may bemanufactured.

The hybrid perovskite particle may have a size that is controllable byadjusting a length or a shape factor of the alkyl halide surfactant. Forexample, the adjustment of the shape factor may be controlled throughthe surfactant having a linear, tapered, or inverted triangular shape.

It is preferable that the generated hybrid perovskite particle has asize of 1 nm to 900 nm. Here, the size of the particle represents a sizewithout considering a size of the ligand that will be described later,i.e., a size of a remaining portion except for the ligand.

If the hybrid perovskite particle has a size exceeding 900 nm, it is afundamental problem in which the large non-radiative decay of theexcitons can occur at room temperature by thermal ionization and thedelocalization of the charge carrier, and a large number of excitons areseparated as free charge carriers and then annihilated.

FIG. 4 is a schematic view illustrating a method for manufacturing thehybrid perovskite particle light-emitter having the 2D structureaccording to an embodiment of the present invention.

Referring to FIG. 4 (a), the first solution in which the hybridperovskite is dissolved in the polar solvent is added dropwise into thesecond solution in which the alkyl halide surfactant is dissolved in thenon-polar solvent.

Referring to FIG. 4 (b), when the first solution is added to the secondsolution, the hybrid perovskite is precipitated from the second solutiondue to a difference in solubility. A surface of the precipitated hybridperovskite is surrounded by the alkyl halide surfactant and thusstabilized to generate a hybrid perovskite particle light-emitter 100that is well dispersed. Here, the surface of the halide perovskitenanocrystal structure is surrounded by the organic ligands that includealkyl halide, inorganic binary compounds or combination thereof.

Thereafter, the polar solvent including the hybrid perovskite particlethat is dispersed in the non-polar solvent, in which the alkyl halidesurfactant is dissolved, may be heated and thus selectively evaporated,or a co-solvent, in which all the polar and non-polar solvents arecapable of being dissolved, may be added to selectively extract thepolar solvent including the particle from the non-polar solvent, therebyobtaining the hybrid perovskite particle light-emitter.

The hybrid perovskite particle light-emitter having the 2D structureaccording to an embodiment of the present invention will be described.

The hybrid perovskite particle light-emitter according to an embodimentof the present invention may include a halide perovskite nanocrystalstructure that has the 2D structure and is dispersible in an organicsolvent. Here, the organic solvent may be the polar solvent or thenon-polar solvent. For example, the polar solvent may includedimethylformamide, gamma butyrolactone, N-methylpyrrolidone,dimethylsulfoxide or isopropyl alcohol, and the non-polar solvent mayinclude dichloroethylene, trichlorethylene, chloroform, chlorobenzene,dichlorobenzene, styrene, dimethylformamide, dimethylsulfoxide, xylene,toluene, cyclohexene.

Also, the particle may have a spherical, cylindrical, cylindroid,polyprism or two-dimensional (lamellar, plate) shape.

Also, the particle may have a size of 1 nm to 900 nm. Here, the size ofthe particle represents a size without considering a size of the ligandthat will be described later, i.e., a size of a remaining portion exceptfor the ligand. For example, when the particle has the spherical shape,the particle may have a diameter of 1 nm to 900 nm.

Also, the particle may have bandgap energy of 1 eV to 5 eV. Thus, sincethe energy bandgap is determined according to the composition and thecrystal structure of the particle, the composition of the particle maybe adjusted to emit light having a wavelength of, for example, 200 nm to1300 nm.

Also, the plurality of organic ligands surrounding the halide perovskitenanocrystal structure may be further provided.

Hereinafter, embodiments of the present invention will be described withreference to FIG. 5.

FIG. 5 is a schematic view of a hybrid perovskite particle light-emitterand an inorganic metal halide perovskite particle light-emitteraccording to an embodiment of the present invention.

Here, FIG. 5 illustrates the hybrid perovskite particle light-emitter.If the hybrid perovskite of FIG. 5 is changed into the inorganic metalhalide perovskite, since the inorganic metal halide perovskite particlelight-emitter is provided, their descriptions are the same.

Referring to FIG. 5, the light-emitter according to an embodiment of thepresent invention may be the hybrid perovskite particle light-emitter orthe inorganic metal halide perovskite particle light-emitter andincludes a halide perovskite nanocrystal structure or inorganic metalhalide perovskite nanocrystal structure 110 that is dispersible in theorganic solvent.

Also, the hybrid perovskite having the 2D crystal structure may be astructure of A2BX₄.ABX₄, or An−₁PbnX3n+1 (where, n is an integer between2 to 6).

Here, the A is an organic ammonium or inorganic inorganic alkali metalmaterial, the B is a metal material, and the X is a halogen element. Forexample, the A may be (CH3NH3)nr ((CxH2x+1)nNH2) (CH2NH3)nr R(NH2)2r(CnH2n+1NH3), CF3NH3, (CF₃NH₃)_(n),((C_(x)F_(2x−1))_(n)NH₂)(CF₂NH₃)_(n), ((C_(x)F_(2x+1))_(n)NH₃),(C_(n)F_(2n+1)NH₃), (CH(NF₂)₂), CxH₂x+1 (C(NH₂)₂), metal, Cs, Rb, K, orderivative thereof (R is alkyl or fluoroalkyl, where n is an integerequal to or greater than 1, and x is an integer equal to or greater than1). Here, the B may be a divalent transition metal, a rare earth metal,an alkali earth metal, Pb, Sn, Ge, Ga, In, Al, Sb, Bi, Po, or acombination thereof. Here, the rare earth metal may be, for example, Ge,Sn, Pb, Eu, or Yb. Also, the alkali earth metal may be, for example, Caor Sr. Also, the X may be Cl, Br, I, or a combination thereof.

The hybrid perovskite particle light-emitter 100 having the 2D structureaccording to the present invention may further include a plurality oforganic ligands 120 or combination thereof surrounding theabove-described hybrid or metal halide perovskite nanocrystal structure110. Each of the organic ligands 120 may include alkyl halide.

Also, the alkyl halide surfactant may have a structure of alkyl-X. Here,the halogen element corresponding to the X may include Cl, Br, or I.Also, the alkyl structure may include acyclic alkyl having a structureof CnH₂ n+1r primary alcohol having a structure such as C_(n)H_(2n+1)OH,secondary alcohol, tertiary alcohol, alkylamine having a structure ofalkyl-N (e.g.′ hexadecyl amine, 9-Octadecenylamine 1-Amino-9-octadecenep-substituted aniline, phenyl ammonium, or fluorine ammonium, but is notlimited thereto.

Also, the inorganic metal halide perovskite having the 2D crystalstructure may be a structure of A₂BX₄, ABX₄, or An−1PbnX₃n+1 (where, nis an integer between 2 to 6).

The A may be an alkali metal, the B may be a divalent divalenttransition metal, a rare earth metal, an alkali earth metal, Pb, Sn, Ge,Ga, In, Al, Sb, Bi, Po, or a combination thereof, and the X may be Cl,Br, I, or a combination thereof. Here, the rare earth metal may be, forexample, Ge, Sn, Pb, Eu, or Yb. Also, the alkali earth metal may be, forexample, Ca or Sr.

The inorganic metal halide perovskite particle light-emitter having the2D structure according to the present invention may further include aplurality of organic ligands surrounding the above-described inorganicmetal halide perovskite nanocrystal structure. Each of the organicligands may include alkyl halide.

Referring again to FIG. 2, a first organic ligand of the hybridperovskite particle light-emitter is substituted with a second organicligand in the solution (S200).

Here, the second organic ligand having a length less than that of thefirst organic ligand or including a phenyl group or a fluorine group maybe added to the solution to substitute the first organic ligand with thesecond organic ligand. Here, heat may be applied to perform substitutionreaction.

Each of the second organic ligands may include alkyl include alkylhalide. Also, the second organic ligand may have a structure ofalkyl-X′. Here, the halogen element corresponding to the X′ may includeCl, Br, or I. Also, the alkyl structure may include acyclic alkyl havinga structure of CnH₂ n+1r primary alcohol having a structure such as CnH₂n+1OH, secondary alcohol, tertiary alcohol, alkylamine having astructure of alkyl-N (e.g.′ hexadecyl amine, 9-Octadecenylamine1-Amino-9-octadecene (C₁₉H₃₇N)), p-substituted aniline, phenyl ammonium,or fluorine ammonium, but is not limited thereto.

Also, the second organic ligand may include alkyl halide, and thehalogen element of the second organic ligand may be an element having ahigher affinity for a center metal of the halide perovskite nanocrystalstructure than that of the halogen element of the first organic ligand.

For example, when the first organic ligand is CH₃ (CH₂)₁₇NH₃Br, CH₃(CH₂)₈NH₃I as an alkali halide surfactant having a short length andincluding the halogen element that has a higher affinity for a centermetal of the halide perovskite nanocrystal structure than that of thehalogen element of the first organic ligand may be added and then heatedto perform the organic ligand substitution. Thus, CH₃ (CH₂)₈NH₃I maybecome the second organic ligand surrounding the nanocrystal structure,and thus, the organic ligand of the particle light-emitter may bereduced in length.

As described above, in the hybrid perovskite particle light-emitteraccording to the present invention, the alkyl halide (the first organicligand) used as the surfactant for stabilizing the surface of theprecipitated hybrid perovskite may surround the surface of the hybridperovskite to form the nanocrystal structure.

If the alkyl halide surfactant has a short length, length, the formedparticle may increase in size to exceed 900 nm. In this case, the lightemission of the exciton may not occur by thermal ionization and thedelocalization of the charge carriers in the large particle, and theexciton may be separated as the free charge carriers and thenannihilated.

That is, the size of the formed hybrid perovskite particle is inverselyproportional to the length of the alkyl halide surfactant used forforming the particle.

Thus, the size of the hybrid perovskite particle formed by using thealkyl halide having a predetermined length or more as the surfactant maybe controlled to a predetermined size or less. For example,octadecyl-ammonium bromide may be used as the alkyl halide surfactant toform the hybrid perovskite particle having a size of a 900 nm or less.

Thus, the alkyl halide (the first organic ligand) having a predeterminedlength or more may be used to form the particle having a predeterminedsize or more, and then, the first organic ligand may be substituted withthe ligand having the short length or including the phenyl group or thefluorine group to more increase the energy transfer or the chargeinjection in the nanocrystal structure, thereby more improving theluminescent efficiency. Furthermore, durability (or stability) may alsobe improved by the substituted hydrophobic ligand.

The substitution step (S200) will be described in more detail withreference to FIG. 6.

FIG. 6 is a schematic view illustrating a method for manufacturing thehybrid perovskite particle light-emitter, in which the organic ligand issubstituted, according to an embodiment of the present invention.

Referring to FIG. 6(a), the hybrid perovskite particle light-emitter 100including the halide perovskite nanocrystal structure 110 and the firstorganic ligand 120 surrounding the nanocrystal structure 110 isprepared. The particle light-emitter 100 may be prepared in state (aliquid state) that is contained in a solution. As illustrated in thedrawings, Pb may be described as an example of the center metal of thehalide perovskite nanocrystal structure 110.

Next, the second organic ligand 130 is added to the solution containingthe particle light-emitter 100.

Referring to FIG. 6(b), since the second organic ligand 130 is added,the first organic ligand 120 is substituted with the second organicligand 130. The organic ligand substitution may be performed by using anintensity difference in affinity between the center metal of the halideperovskite nanocrystal structure 110 and the halogen element. Forexample, the affinity with the center metal may increase in order ofCl<Br<I.

Thus, when the halogen element X of the first organic ligand 120 is Cl,the ligand substitution may be performed by using Br or I as the halogenelement X′ of the second organic ligand 130.

Thus, the first organic ligand 120 may be substituted with the secondorganic ligand 130 having the short length and including the fluorinegroup to form a hybrid perovskite particle light-emitter 100′ which hasimproved luminescent efficiency and in which the organic ligand issubstituted.

A method for manufacturing the inorganic metal halide metal halideperovskite particle light-emitter, in which the organic ligand issubstituted, according to an embodiment of the present invention will bedescribed.

The method for manufacturing the inorganic metal halide perovskiteparticle light-emitter, in which the organic ligand is substituted mayinclude a step of preparing a solution including an inorganic metalhalide perovskite particle light-emitter including an inorganic metalhalide perovskite nanocrystal structure and a plurality of first organicligands surrounding a surface of the inorganic metal halide perovskitenanocrystal structure and a step of adding a second organic ligandhaving a short length or including a phenyl group or a fluorine group tosubstitute the first organic ligand with the second organic ligand.

Each of the first organic ligand and the second organic ligand mayinclude alkyl halide, and the halogen element of the second organicligand may be an element having affinity equal to or higher than that ofthe halogen element of the first organic ligand with respect to a centermetal of the halide perovskite nanocrystal structure.

The inorganic metal halide perovskite material may include a structureof ABX₃, A₂BX₄, ABX₄, or An−1PbnX₃n+1 (n is an integer between 2 to 6),where the A may be an alkali metal, the B may be a metal material, andthe X may be a halogen element.

Here, the A may be Na, K, Rb, Cs, or Fr, the B may be a divalenttransition metal, a rare earth metal, an alkali earth metal, Pb, Sn, Ge,Ga, In, Al, Sb, Bi, Po, or a combination thereof, and the X may be Cl,Br, I, or a combination thereof.

Here, the substitution methods may be the same except same except that,in the “inorganic metal halide” perovskite particle, an A site materialis an alkali metal, and in the “hybrid” perovskite particle, an A sitematerial is an organic ammonium material. Thus, the method forsubstituting the organic ligand of the inorganic metal halide perovskiteparticle is the same as that for manufacturing the hybrid perovskiteparticle light-emitter in which the organic ligand is substituted, andthus, its detailed description will be omitted.

A light emitting device according to an embodiment of the presentinvention will be described.

A light emitting device according to an embodiment of the presentinvention may be a device using a light emitting layer including anhalide perovskite nanocrystal light-emitter in which an organic ligandis substituted or an inorganic metal halide perovskite particlelight-emitter in which an organic ligand is substituted. Here, thehalide perovskite nanocrystal light-emitter in which the organic ligandis substituted or the inorganic metal halide perovskite particlelight-emitter in which the organic ligand is substituted may bemanufactured through the above-described manufacturing methods.

For example, the light emitting device according to the presentinvention may include a first electrode, a second electrode, and a lightemitting layer disposed between the first electrode and the secondelectrode and including the halide perovskite nanocrystal light-emitterin which the organic ligand is substituted or the inorganic metal halideperovskite particle light-emitter in which the organic ligand issubstituted.

For another example, the hybrid perovskite particle in which the organicligand is substituted or the inorganic metal halide perovskite particlein which the organic ligand is substituted may be applied to a solarcell by using a photoactive layer including the above-described hybridperovskite particle and the inorganic metal halide perovskite particle.The solar cell may include a first electrode, a second electrode, and aphotoactive layer disposed between the first electrode and the secondelectrode and including the above-described perovskite particle.

MANUFACTURING EXAMPLE 1

A hybrid perodvskite nanocrystal colloidal particle light-emitter havinga 3D structure according to an embodiment of the present invention wasformed. The inorganic metal halide perovskite nanocrystal colloidalparticle light-emitter was formed through an inverse nano-emulsionmethod, or reprecipitation method, or hot injection method.

Particularly, hybrid perovskite was dissolved in a polar solvent toprepare a first solution. Here, dimethylformamide was used as the polarsolvent, and CH₃NH₃PbBr₃ was used as the hybrid perovskite. Here, theused CH₃NH₃PbBr₃ was prepared by mixing CH₃NH₃Br with PbBr₂ at a ratioof 1:1.

Also, a second solution in which an alkyl halide surfactant is dissolvedin a non-polar solvent was prepared. Here, toluene was used as thenon-polar solvent, and octadecylammonium bromide alkyl (C₃(C₂)₁₇NH₃Br)was used as the halide surfactant.

Then, the first solution slowly dropped drop wise into the secondsolution that is being strongly stirred to form the hybrid perovskitenanocrystal colloidal particle light-emitter having the 3D structure.

Then, the hybrid perovskite colloidal particle that is in a liquid statewas spin-coated on a glass substrate to form a hybrid perovskiteparticle thin film (perovskite-NP film)

Here, the formed hybrid perovskite particle has a size of about 20 nm.

MANUFACTURING EXAMPLE 2

The same process as that according to Manufacturing Example 1 wasperformed, and CH₃(CH₂)₁₃NH₃Br was used as an alkyl halide surfactant toform a hybrid perovskite nanocrystal colloidal particle light-emitterhaving a 3D structure according to an embodiment of the presentinvention.

Here, the formed hybrid perovskite particle has a size of about 100 nm.

MANUFACTURING EXAMPLE 3

The same process as that according to Manufacturing Example 1 wasperformed, and CH₃(CH₂)₁₀NH₃Br was used as an alkyl halide surfactant toform a hybrid perovskite particle light-emitter having a 3D structureaccording to an embodiment of the present invention.

Here, the formed hybrid perovskite particle has a size of about 300 nm.

MANUFACTURING EXAMPLE 4

The same process as that according to Manufacturing Example 1 wasperformed, and CH₃(CH₂)₇NH₃Br was used as an alkyl halide surfactant toform a hybrid perovskite particle light-emitter having a 3D structureaccording to an embodiment of the present invention.

Here, the formed hybrid perovskite particle has a size of about 500 nm.

MANUFACTURING EXAMPLE 5

The same process as that according to Manufacturing Example 1 wasperformed, and CH₃(CH₂)₄NH₃Br was used as an alkyl halide surfactant toform a hybrid perovskite particle light-emitter having a 3D structureaccording to an embodiment of the present invention.

Here, the formed hybrid perovskite particle has a size of about 700 nm.

MANUFACTURING EXAMPLE 6

The same process as that according to Manufacturing Example 1 wasperformed, and CH 3CH 2NH 3Br was used as an alkyl halide surfactant toform a hybrid perovskite particle light-emitter having a 3D structureaccording to an embodiment of the present invention.

Here, the formed hybrid perovskite particle has a size of about 800 nm.

MANUFACTURING EXAMPLE 7

The same process as that according to Manufacturing Example 1 wasperformed, and CH₃NH₃Br was used as an alkyl halide surfactant to form ahybrid perovskite particle light-emitter having a 3D structure accordingto an embodiment of the present invention.

Here, the formed hybrid perovskite particle has a size of about 900 nm.

MANUFACTURING EXAMPLE 8

A hybrid perovskite particle light-emitter having a 3D structureaccording to an embodiment of the present invention was formed. Theinorganic metal halide perovskite particle light-emitter was formedthrough an inverse nano-emulsion method, or reprecipitation method, orhot injection method.

Particularly, hybrid perovskite was dissolved in a polar solvent toprepare a first solution. Here, dimethylformamide was used as the polarsolvent, and (CH₃NH₃)₂PbBr₃ was used as the hybrid perovskite. Here, theused CH₃NH₃PbBr₃ was prepared by mixing CH₃NH₃Br with PbBr₂ at a ratioof 1:1.

Also, a second solution in which an alkyl halide surfactant is dissolvedin a non-polar solvent was prepared. Here, toluene was used as thenon-polar solvent, and octadecylammonium bromide (CH₃(CH₂)₁₇NH₃Br) wasused as the alkyl halide surfactant.

Then, the first solution slowly dropped drop wise into the secondsolution that is being strongly stirred to form a hybrid perovskiteparticle light-emitter having a 2D structure. Here, the formed hybridperovskite particle has a size of about 20 nm.

Then, CH₃ (CH₂)₈NH₃I as an alkyl halide surfactant may surfactant may beadded to the second solution and heated to perform the organic ligandsubstitution. Thus, CH₃(CH₂)₈NH₃I may become the second organic ligandsurrounding the nanocrystal structure. Thus, the hybrid perovskiteparticle light-emitter, in which the organic ligand is substituted,including the halide perovskite nanocrystal structure having a size ofabout 20 nm and the CH₃(CH₂)₈NH₃I organic ligand surrounding thenanocrystal structure was manufactured.

MANUFACTURING EXAMPLE 9

The same process as that according to Manufacturing Example 1 wasperformed, and (CH₃NH₃)₂PbCl₄ was used as the hybrid perovskite. Here,the used (CH₃NH₃)₂PbCl₄ was prepared by mixing CH₃NH₃Cl with PbCl₂ at aratio of 2:1.

Here, the formed hybrid perovskite nanocrystalline particle emits lightnear to ultraviolet or blue color. The light emission spectrum islocated at about 380 nm.

MANUFACTURING EXAMPLE 10

The same process as that according to Manufacturing Example 1 wasperformed, and (CH₃NH₃)₂Pbi₄ was used as the hybrid perovskite. Here,the used (CH₃NH₃)₂Pbi₄ was prepared by mixing CH₃NH₃I with Pbi2 at aratio of 2:1.

Here, the formed hybrid perovskite nanocrystalline particle emits lightnear to infrared or red color. The light emission spectrum is located atabout 780 nm.

MANUFACTURING EXAMPLE 11

The same process as that according to Manufacturing Example 1 wasperformed, and (CH₃NH3)₂PbCl_(x)Br_(4-x) was used as the hybridperovskite. Here, the used (CH₃NH₃)₂PbCl_(x)Br₄, was prepared by mixingCH₃NH₃Cl with PbBr₂ at a ratio of 2:1.

Here, the light emission spectrum of the formed hybrid perovskitenanocrystalline particle is located between 380 nm and 520 nm.

MANUFACTURING EXAMPLE 12

The same process as that according to Manufacturing Example 1 wasperformed, and (CH₃NH₃)₂PbI_(x)Br_(4-x) was used as the hybridperovskite. Here, the used (CH₃NH₃)₂PbI_(x)Br_(4-x) was prepared bymixing CH₃NH₃I with PbBr₂ at a predetermined ratio.

Here, the light emission spectrum of the formed hybrid perovskitenanocrystalline particle is located between 520 nm and 780 nm.

MANUFACTURING EXAMPLE 13

The same process as that according to Manufacturing Example 1 wasperformed, and (CH(NH2)₂)₂Pbi₄ was used as the hybrid perovskite. Here,the used (CH(NH₂)₂)₂Pbi₄ was prepared by mixing CH(NH)₂I with PbI₂ at aratio of 2:1.

Here, the light emission spectrum of the formed hybrid perovskitenanocrystalline particle emits infrared light and is located at about800 nm.

MANUFACTURING EXAMPLE 14

The same process as that according to Manufacturing ManufacturingExample 1 was performed, and (CH₃NH₃)₂Pb_(x)Sn_(1-x)I₄ was used as thehybrid perovskite. Here, the used (CH₃NH₃)₂Pb_(x)Sn_(1-x)I₄ was preparedby mixing CH₃NH₃I with PbxSn_(1-x)I₂ at a ratio of 2:1.

Here, the light emission spectrum of the formed hybrid perovskitenanocrystalline particle is located between 820 nm and 1120 nm.

MANUFACTURING EXAMPLE 15

The same process as that according to Manufacturing Example 1 wasperformed, and (CH₃NH₃)₂Pb_(x)Sn_(1-x)Br₄ was used as the hybridperovskite. Here, the used (CH₃NH₃)₂Pb_(x)Sn_(1-x)Br₄ was prepared bymixing CH₃NH₃Br with Pb_(x)Sn_(1-x)Br₂ at a ratio of 2:1.

Here, the light emission spectrum of the formed hybrid perovskitenanocrystalline particle is located between 540 nm and 650 nm.

MANUFACTURING EXAMPLE 16

The same process as that according to Manufacturing Example 1 wasperformed, and (CH₃NH₃)₂Pb_(x)Sn_(1-x)Cl₄ was used as the hybridperovskite. Here, the used (CH₃NH₃)₂Pb_(x)Sn_(1-x)Cl₄ was prepared bymixing CH₃NH₃C1 with Pb_(x)Sn_(1-x)Cl₂ at a ratio of 2:1.

Here, the light emission spectrum of the formed hybrid perovskitenanocrystalline particle is located between 400 nm and 460 nm.

MANUFACTURING EXAMPLE 17

The same process as that according to Manufacturing Example 1 wasperformed, and (C₄H₉NH₃)PbBr₄ was used as the hybrid perovskite. Here,the used (C₄H₉NH₃)PbBr₄ was prepared by mixing (C₄H₉NH₃)Br with PbBr₂ ata ratio of 2:1.

Here, the light emission spectrum of the formed hybrid perovskitenanocrystalline particle is located at about 411 nm.

MANUFACTURING EXAMPLE 18

The same process as that according to Manufacturing Example 1 wasperformed, and (C₅H₁₁NH₃)PbBr₄ was used as the hybrid perovskite. Here,the used (C₅H₁₁NH₃)PbBr₄ was prepared by mixing (C₅H₁₁NH₃)Br with PbBr₂at a ratio of 2:1.

Here, the light emission spectrum of the formed hybrid perovskitenanocrystalline particle is located at about 405 nm.

MANUFACTURING EXAMPLE 19

The same process as that according to Manufacturing Example 1 wasperformed, and (C₇H₁₅NH₃)PbBr₄ was used as the hybrid perovskite. Here,the used (C₇H₁₅NH₃)PbBr₄ was prepared by mixing (C₇H₁₅NH₃)Br with PbBr₂at a ratio of 2:1.

Here, the light emission spectrum of the formed hybrid perovskitenanocrystalline particle is located at about 401 nm.

MANUFACTURING EXAMPLE 20

The same process as that according to Manufacturing Example 1 wasperformed, and (C₁₂H₂₅NH₃)PbBr₄ was used as the hybrid perovskite. Here,the used (C₁₂H₂₅NH₃)PbBr₄ was prepared by mixing (C₁₂H₂₅NH₃)Br withPbBr₂ at a ratio of 2:1.

Here, the light emission spectrum of the formed hybrid perovskitenanocrystalline particle is located at about 388 nm.

MANUFACTURING EXAMPLE 21

The inorganic metal halide perovskite particle light-emitter accordingto an embodiment of the present invention was formed. The inorganicmetal halide perovskite particle light-emitter was formed through aninverse nano-emulsion method, or reprecipitation method, or hotinjection method.

Particularly, Cs₂CO₃ and an oleic acid were added to octadecene (ODE)that is a non-polar solvent to react at a high temperature, therebypreparing a third solution. PbBr₂, the oleic acid, and oleylamine wereadded to the non-polar solvent to react for one hour at a hightemperature (120° C.), thereby preparing a fourth solution.

Then, the third solution slowly dropped drop wise into the fourthsolution that is being strongly stirred to form the inorganic metalhalide perovskite (CsPbBr₃) particle light-emitter having the 3Dstructure.

Then, the inorganic metal halide perovskite particle that is dispersedin the solution was spin-coated on a glass substrate to form aninorganic halide perovskite particle thin film (perovskite-NP film).

Here, the formed inorganic metal halide perovskite particle has a sizeof about 20 nm.

MANUFACTURING EXAMPLE 22

The organic ligand of the inorganic metal halide halide perovskiteparticle according to Manufacturing Example 21 was substituted.

First, the fourth solution in which the inorganic metal halideperovskite particle according to Manufacturing Example 21 is dispersedwas prepared.

Then, CH₃(CH₂)₈NH₃I as an alkyl halide surfactant may be added to thefourth solution and heated to perform the organic ligand substitution.Thus, CH₃(CH₂)₈NH₃I may become the second organic ligand surrounding thenanocrystal structure. Thus, the inorganic metal halide perovskiteparticle light-emitter, in which the organic ligand is substituted,including the inorganic metal halide perovskite nanocrystal structurehaving a size of about 20 nm and the CH₃(CH₂)₈NH₃I organic ligandsurrounding the nanocrystal structure was manufactured.

MANUFACTURING EXAMPLE 23

A light emitting device according to an embodiment of the presentinvention was manufactured.

First, after an ITO substrate (a glass substrate coated with an ITOanode) is performed, PEDOT: PSS (AI4083 from Heraeus company) that is aconductive material was spin-coated on the ITO anode and then thermallytreated for 30 minutes at a temperature of 150° C. to form a holeinjection layer having a thickness of 40 nm.

The solution in which the hybrid perovskite particle light-emitter, inwhich the organic ligand is substituted, according to ManufacturingExample 8 is dispersed was spin-coated on the hole injection layer andthen thermally treated for 20 minutes at a temperature of 80° C. to forman hybrid perovskite particle light emitting layer.

Thereafter, 1,3,5-Tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBI)having a thickness of 50 nm was deposited on the hybrid perovskiteparticle light emitting layer under a high vacuum state of 1×10⁻⁷ Torror more to form an electron transport layer, and then, LiF having athickness of 1 nm was deposited on the electron transport layer to forman electron injection layer. Then, aluminum having a thickness of 100 nmwas deposited on the electron injection layer to form a cathode, therebymanufacturing a hybrid perovskite particle light emitting device.

MANUFACTURING EXAMPLE 24

A solar cell according to an embodiment of the present invention wasmanufactured.

First, after an ITO substrate (a glass substrate coated with an ITOanode) is performed, PEDOT: PSS (AI4083 from CLEVIOS PH company) that isa conductive material was spin-coated on the ITO anode and thenthermally treated for 30 minutes at a temperature of 150° C. to form ahole extraction layer having a thickness of 40 nm.

The hybrid perovskite particle, in which the organic ligand issubstituted, according to Manufacturing Example 1 was mixed withPhenyl-C61-butyric acid methyl ester (PCBM) and then applied to the holeextraction layer to form a photoactive layer, and Al having a thicknessof 100 nm was deposited on the photoactive layer to manufacture aperovskite particle solar cell.

COMPARATIVE EXAMPLE 1

CH₃NH₃PbBr₃ was dissolved in dimethylformamide that is a polar solventto manufacture a first solution.

Then, the first solution was spin-coated on a glass substrate tomanufacture a CH₃NH₃PbBr₃ thin film (perovskite film).

COMPARATIVE EXAMPLE 2

CH₃NH₃PbCl₃ was dissolved in dimethylformamide that is a polar solventto manufacture a first solution.

Then, the first solution was spin-coated on a glass substrate tomanufacture a CH₃NH₃PbCl₃ thin film (perovskite film).

EXPERIMENTAL EXAMPLE

FIG. 7 is a fluorescent image obtained by photographing emission lightby irradiating ultraviolet rays onto a light-emitter according toManufacturing Example 1, Comparative Example 1, and Comparative Example2.

Referring to FIG. 7, it is seen that a hybrid perovskite solution, whichis not in the form of a nanocrystal, but in the form of a bulk,according to Comparative Example 1 and Comparative Example 2 emits darklight, but the luminescent material having the nanocrystal according toManufacturing Example 1 emits very bright green light.

Also, as a result of measuring the photoluminescence photoluminescencequantum yield (PLQY), it is seen that the hybrid perovskite particlelight-emitter according to Manufacturing Example 1 has a very high valueof 52%.

On the other hand, in Comparative Example 1 and Comparative Example 2,the hybrid perovskite having the form of the thin film, which ismanufactured by spin-coating on the glass substrate, had a PLQY value ofabout 1%.

FIG. 8 is a schematic view of a light-emitter according to ManufacturingExample 1 and Comparative Example 1.

FIG. 8(a) is a schematic view of a light-emitter thin film (perovskitefilm) according to Comparative Example 1, FIG. 8 (b) is a schematic viewof a light-emitter thin film (perovskite-NP film) according toManufacturing Example 1. Referring to FIG. 8(a), the particle accordingto Comparative Example 1 has the form of the thin film manufactured byspin-coating the first solution on the glass substrate. Referring toFIG. 8 (b), the light-emitter according to Manufacturing Example 1 hasthe form of the nanocrystal structure 110.

FIG. 9 is an image obtained by photographing a photoluminescence matrixof the light-emitter at room temperature and a low temperature accordingto Manufacturing Example 30 and Comparative Example 1.

FIG. 9(a) is an image obtained by photographing a photographing a lightemission matrix of the thin film-shaped hybrid perovskite (perovskitefilm) according to Comparative Example 1 at a low temperature (70K), andFIG. 9(b) is an image obtained by photographing a light emission matrixof the thin film-shaped hybrid perovskite (perovskite film) according toComparative Example 1 at room temperature.

FIG. 9(c) is an image obtained by photographing a photoluminescencematrix of the thin film (perovskite-NP film) including the hybridperovskite particle according to Manufacturing Example 1 at a lowtemperature (70K), and FIG. 9(d) is an image obtained by photographing aphotoluminescence matrix of the thin film (perovskite-NP film) of thehybrid perovskite particle according to Manufacturing Example 1 at roomtemperature.

Referring to FIGS. 9(a) and 9(d), in case of the perovskite-NP film(perovskite-NP film) according to Manufacturing Example 1, it is seenthat photoluminescence occurs at the same position as that of theperovskite film according to Comparative Example 1, and color purity ismore improved. Also, in case of the perovskite-NP film according toManufacturing Example 1, it is seen that photoluminescence having highcolor purity occurs at room temperature at the same position as that atthe low temperature, and intensity of the light emission is not reduced.On the other hand, the hybrid perovskite according to ComparativeExample 1 has different color purity and light emission position at roomtemperature and low temperature, and exciton does not emit light due tothermal ionization and delocalization of charge carriers at roomtemperature and thus is separated as free charge carriers andannihilated to cause low light emission intensity.

FIG. 10 is a graph obtained by photographing photoluminescence of thelight-emitter according to Manufacturing Example 1 and ComparativeExample 1.

Referring to FIG. 10, in all cases of the liquid state in which thehybrid perovskite particle light-emitter is contained in the solutionand the thin film state in which the thin film layer is formed by usingthe particle light-emitter according to Manufacturing Example 1, it isseen that the photoluminescence occurs at the same position as thehybrid perovskite according to Manufacturing Example 1.

FIG. 11 is a schematic view of the hybrid perovskite Particlelight-emitter, in which the organic ligand is substituted, according toan embodiment of the present invention.

Referring to FIG. 11, the hybrid perovskite particle light-emitter 100manufactured through the manufacturing methods of the present inventionmay be substituted with the organic ligand containing a hydrophobic aphenyl group or fluorine group, for example, fluorine ammonium. Thus,since the hybrid perovskite particle light-emitter is substituted withthis kind of ligand, it is seen that the manufactured hybrid perovskiteparticle light-emitter 100′ is more improved in durability (orstability).

In the particle light-emitter including the halide perovskitenanocrystal structure, the hybrid perovskite having the crystalstructure, in which the FCC and the BCC are combined with each other,may be formed in the particle light-emitter to form a lamellar structurein which the organic plane and the inorganic plane are alternatelystacked, and also, the excitons may be confined in the inorganic planeto implement the high color purity.

Also, the exciton diffusion length may be reduced, and the excitonbinding energy may increase in the nanocrystal having a size of 900 nmor less to prevent the excitons from being annihilated by thermalionization and the delocalization of the charge carriers, therebyimproving the luminescent efficiency at room temperature.

Also, the bandgap energy of the hybrid perovskite particle may bedetermined by the crystal structure without depending on the particlesize.

Furthermore, since the 2D hybrid perovskite is synthesized into thenanocrystal when compared to the 3D hybrid perovskite, the excitonbinding energy may be improved to more improve the luminescentefficiency and the durability (or stability)

Also, the organic ligand surrounding the hybrid perovskite or inorganicmetal halide perovskite nanocrystal may be substituted with the ligandhaving the short length or the ligand including the phenyl group or thefluorine group to more increase the energy transfer or the chargeinjection in the nanocrystal structure, thereby improving theluminescent efficiency and the durability (or stability) by thehydrophobic ligands.

It should be noted that the embodiments of the present inventiondisclosed in the present specification and drawings are onlyillustrative of specific examples for the purpose of understanding andare not intended to limit the scope of the present invention. It is tobe understood by those skilled in the art that other modifications basedon the technical idea of the present invention are possible in additionto the embodiments disclosed herein.

DESCRIPTION OF SYMBOLS

-   -   100: Hybrid perovskite particle light-emitter    -   100′: Hybrid perovskite particle light-emitter in which organic        ligand is substituted    -   110: Hybrid perovskite nanocrystal structure    -   120: First organic ligand 130: Second organic ligand

The invention claimed is:
 1. A method for manufacturing a hybridperovskite particle light-emitter, in which halide perovskitenanocrystal and a substituted organic ligand are included, the methodcomprising: preparing a solution comprising the hybrid perovskiteparticle light-emitter including an halide perovskite nanocrystalstructure and a plurality of first organic ligands surrounding a surfaceof the halide perovskite nanocrystal; and substituting at least one ofthe first organic ligands with a second organic ligand, which has alength less than that of each of the first organic ligands; wherein thesecond organic ligand comprises an element having affinity higher thanthat of the first organic ligands.
 2. The method of claim 1, wherein thehybrid perovskite particle has a size of 1 nm to 900 nm.
 3. The methodof claim 1, wherein the hybrid perovskite particle has bandgap energydetermined by the crystal structure without depending on a particlesize.
 4. The method of claim 1, wherein the preparing of the solutioncomprising the hybrid perovskite particle light-emitter comprises:preparing a first solution in which hybrid perovskite is dissolved in apolar solvent and a second solution in which an alkyl halide surfactantis dissolved in a non-polar solvent; and mixing the first solution withthe second solution to form the hybrid perovskite particlelight-emitter.
 5. The method of claim 4, wherein the hybrid perovskitecomprises a structure of ABX₃, A₂BX₄, ABX₄, A_(n)BX_(2+n), A₂BB′X₆, orA_(n−1)Pb_(n)X_(3n+1) (where n is an integer between 2 to 6), and the Ais an organic ammonium material, the B or B′ is a metal material, andthe X is a halogen element.
 6. The method of claim 5, wherein the A is(CH₃NH₃)_(n), ((C_(x)H_(2x+1))_(n)NH₂)(CH₂NH₃)_(n), (R(NH₃)₂,(C_(n)H_(2n+1)NH₃)₂, CF₃NH₃, (CF₃NH₃)_(n),((C_(x)F_(2x+1))_(n)NH₂)(CF₂NH₃)_(n), ((C_(x)F_(2x−1))_(n)NH₃), metal,(CH(NH₂)₂), C_(x)H_(2x−1)(C(NH₂)₂), (C_(n)F_(2n+1)NH₃) or derivativethereof (where n is an integer equal to or greater than 1, and x is aninteger equal to or greater than 1), the B or B′ is a divalenttransition metal, a rare earth metal, an alkali earth metal, Pb, Sn, Ge,Ga, In, Al, Sb, Bi, Po, or a combination thereof, and the X is Cl, Br,I, or a combination thereof.
 7. A hybrid perovskite particlelight-emitter, in which an organic ligand is substituted, manufacturedby the manufacturing method of claim
 1. 8. The hybrid perovskiteparticle light-emitter of claim 7, wherein the hybrid perovskiteparticle light-emitter, in which an organic or inorganic ligand issubstituted, is dispersible in an organic solvent or materials.
 9. Thehybrid perovskite particle light-emitter of claim 8, wherein the organicsolvent comprises a polar solvent and a non-polar solvent, the polarsolvent comprises dimethylformamide, gamma butyrolactone,N-methylpyrrolidone, dimethylsulfoxide or isopropyl alcohol, and thenon-polar solvent comprises dichloroethylene, trichlorethylene,chloroform, chlorobenzene, dichlorobenzene, styrene, xylene, toluene, orcyclohexene.
 10. A light emitting device comprising: a first electrode;a second electrode; and a light emitting layer disposed between thefirst electrode and the second electrode and comprising the hybridperovskite particle light-emitter, in which the organic ligand issubstituted, of claim
 7. 11. A solar cell comprising: a first electrode;a second electrode; and a photoactive layer disposed between the firstelectrode and the second electrode and comprising the hybrid perovskiteparticle light-emitter, in which the organic ligand is substituted, ofclaim
 7. 12. The method of claim 1, wherein each of the first organicligands and the second organic ligand comprises alkyl halide, organicammonium, or surfactant.
 13. The method of claim 1, wherein halogen atomof second organic ligand has affinity higher than that of a halogen atomof the first organic ligands with respect to a center metal of theperovskite nanocrystal structure.